Workpiece-locating vise for use in a machine-tool



R. MOLL Aug. 18, 1964 WORKPIECE-LOCATING VISE FOR USE IN A MACHINE-TOOL.

Filed Feb. 15, 1962 /Nl/EHTOR EaBEkT Mou.. BY fu-wf.

United States Patent O 3,145,022 WORlPlECiZ-MNIA'HNG lildi lFlt USE EN A MMCHENEJEUL Robert Moll, Geneva, Switzerland, assigner to Condor SA., Courtaivre tiura bernois, Switzerland), a corpo ration of witzeriand Filed Feb, lid, 1962, Ser. No, 173,454 Claims priority, application, Switzerland, Feb. il?, wel, ilfQ'/ei l Claims. (Cl. 269-25) This invention relates to a workpiece-locating vise for use in a machine-tool.

According to the present invention the vise comprises supporting structure on which are supported two jaws each controlled by an hydraulic servo-motor supplied with fluid under pressure from a general distributor, and control means for automatically centering a workpiece to be machined by the machine-tool on a reference axis, said control means comprising a secondary distributor consisting of a sheath and of a slide valve member slidably mounted in the sheath, said sheath being itself mounted in said supporting structure for sliding displacement parallel to the slide valve member, at least one of said servomotors being supplied via a conduit with fluid whose flow, pressurization and exhaustion are controlled by a plurality of ports formed in the sheath, the opening and closing of these ports being operated by the slide valve member, the position of the sheath being made dependent on the position of one of the jaws and the position of the slide valve member being made dependent on the position of the other jaw so that by means of said ports the workpiece to be clamped will always be located in the same centering position irrespective of its diameter.

For a better understanding of the invention and to show how the same may be carried into effect, one constructional form of vise according to the invention will now be described, by way of example, with reference to the accompanying drawing which is a diagrammatic cross-section of the vise.

The illustrated workpiece-locating vise is particularly, but not exclusively, intended for use in a machine-tool for lathing and centering workpieces which are subsequently to be nished by other machines, for example the machine-tool disclosed in the specification of my copending patent application No. 173,453, iiled February 15, 1962, now Patent No. 3,110,082, issued November 12, 1963.

The illustrated workpiece-locating vise comprises a supporting frame l having clamping means 2 for mounting the vise on a rod or tube 3 of a machinetool. A iixed slide-bar l to which the frame l can also be releasably clamped is provided on the machine-tool to prevent rotary movement of the vise about rod 3. On the supporting frame l are mounted two jaws 5 and 6 which are controlled by cylinder and piston article clamping units each comprising a servo-motor including a first cylinder 7 and a servo-motor including a second cylinder 8, respectively. law S consists in the present instance of a stem projecting from the piston 9 of the servo-motor 7. I aw 6, which is formed with a V-shaped notch lill, is slidably mounted in a guide il of the supporting frame il. The jaw 6 is rigidly connected to the piston l2 of servo-motor 8 by a stem 13.

The supporting frame l is also formed with a bore 14 extending parallel to the axis of movement of jaws 5 and 6. Bore lli accommodates a secondary pressurized lluid distributor l5 in the form of valve means including a sheath lo and a slide valve member i7 slidably mounted in sheath 16. Sheath 16 is capable of limited sliding movement in the bore 14 as determined by a screw i3 which extends through a threaded bore t9 of the suprce porting frame i and whose point projects into a groove 2li formed in sheath lid. The sheath 16 is also formed on one of its sides with ports 22, 23 and 24 through which the outer surface of the sheath communicates with its internal bore 25. The slide valve member i7 is formed with an annular groove 26 the width of which corresponds substantially to the distance separating ports 22 and 23 in the sheath. On the side opposite ports 22 and 23, the sheath 16 is provided with a port 27, which is located in an axial position intermediate ports 22 and 23 and which opens in a groove 23 formed in the sheath i6. Ports 22 and 23 open in grooves 29' and 30, respectively, groove 3u extending to port 24.

The servo-motors 7 and d are supplied with oil under pressure from a general distributor 31 including two solenoid-operated valves 32 and 33, of which one is open to the atmosphere when the other connects the supply circuit of servo-motors 7 and il to the source of oil under pressure. Conduit 3d, which is controlled by valve 3.2, is connected at 35 and 36 to the servo-motors 7 and 3. Conduit 37, which is controlled by valve 33, directly feeds servo-motor 7' by opening at 3u into the cylinder thereof. This conduit 37 is extended by a passage 39 drilled in the supporting frame il. and terminating at port d@ in groove 3@ of sheath 16. A passage 4l, which is also drilled in the supporting frame il and which terminates at d2, establishes communication between the groove 29 and an exhaust 43. Groove 2S formed in sheath il@ communicates with servo-motor 8 via a port A drilled in the supporting frame il, and `via a conduit i5 which opens in the servo-motor S through a passage 4d.

As will readily be understood from inspection of the circuitry for feeding servo-motors '7 and d, the servomotor 7 is directly supplied with oil from the general distributor 3l for operative movement in both directions. But servo-motor 3 is only directly fed with oil by valve 32 for a vise releasing stroke, it being indirectly controlled by the secondary distributor 1S to bring about a gripping action of the jaws 5 and 6 on a workpiece d'7 to be held. The secondary distributor 15 forms part of means for self-centering workpiece 47 in relation to a reference axis. In this connection, the axial position of sheath lo is made dependent on the position of jaws t5 through the intermediary of a lever 48 which is pivotally mounted at i9 on the supporting frame l and which acts at one end Sti against the adjacent end of sheath 16 and at its opposite end il against the end of a rod 52 projecting from the piston l2 of servo-motor 8.

The slide valve member i7 is subjected to the other jaw 5 through the intermediary of a connecting arm member 53, one end portion of which is engaged over a threaded extension 54 of the slide valve member 17, and the other end portion of which is engaged over a rod S5 projecting from the piston 9 out of the servomotor 7. Member 53 is rigidly secured to the rod 55' by a screw 56. But the position of member S3 on the threaded extension S4 of the slide valve member 17 is adjustable by means of a nut 57 and of a knurled nut Sii between which is clamped the end portion 59 of member 53.

As shown by the drawing, the diameter of piston 9 of servo-motor 7 is smaller than the diameter or piston 12 of servo-motor 8. The servo-motor 7, which is supplied with oil directly from the general distributor, is intended to exert a constant pressure on the workpiece #t7 by its jaw 5 in the course of a clamping operation, the position of jaw 5 being corrected by the greater pressure exerted by jaw 6 actuated by piston i2 of greater diameter. However, the oil supply to servo-motor 8 is regulated by the secondary distributor 15. In this connection and as shown by the drawing, when the jaws 5 and e have been pressed into engagement with the workpiece preparatory saaaoaa f .il

to positioning on the reference axis l2, the servo-motor e is supplied with oil under pressure by the solenoid-operated Valve 33 via conduit 37, passage 39, groove di), port 2li, annular groove 2d, groove 2t?, passage dd and conduit d5. The pressure exerted in servo-motor d is however limited because a leakage of oil occurs via port 22, groove, 29 and passage di towards the exhaust outlet Supposing that during clamping of workpiece 47, the jaw 6 is too far forward in relation to jaw 5, the slide valve member 17, which is lagging, wholly uncovers port 22 by means of its groove 2e and closes the port 23 for admitting oil under pressure, thereby interrupting the supply of oil under pressure to the servodnotor S and bringing it to a stop. The servo-motor 7 canthus proceed witl the forward movement of jaw 5 thereby restoring the balanced condition of jaws 5 and t5 by, if need be, push ing back jaw 6.

lf, however, it is jaw 5 that is too far forward in relation to jaw 6, the slide valve member i7 closes leakage port Y 22 and causes port 23 for admitting oil under pressure to communicate with its groove 2d. Conduit d5 will thus convey a large flow of oil to the servo-motor 8. As the working area of piston l?. or servoarnotor S is greater than that of piston 9 of servonotor 7, the greater thrust of piston 12 enables the latter to push jaw 5 bacicwards to bring workpiece (i7 into its centered position on the reference axis, in which position the thrusts exerted on jaws 5 and -6 become stabilized.

A dcmultiplying mechanism lis provided in the transmission between the tl-shaped jaw o and the secondary distributor constituted in the illustrated embodiment by the sheath io. This demultiplying mechanism is in fact constituted by the lever 43 and is made necessary by the presence of the V-shaped jaw e. inasmuch that the vise must be able to clamp workpieces of diierent diameters and always to center these workpieces on the same reference axis, the possible clamping movement of jaw 6 must necessarily always be greater than that of jaw 5 which has the appearance of an ordinary pusher. if the angle of the V-shaped notch Iii of jaw 6 is 2a and the amplitude of the clamping displacement of jaw 5 is A, then the amplitude of the clamping displacement of jaw d, termed Bj would be equal to sine a It therefore follows that the demultiplication of the displacement of jaw 6 in relation to sheath i6 must be in the ratio of sine a. The ratio between the sheath arm di) of lever 4S and the longer arm (il is therefore equal to sine a.

Between the sheath lo and the slide valve member 17 are provided thrust means tending to move the sheath i6 and the member 17 away from one another in order to take up any transmission play in the return motion from piston 12 to the secondary distributor 15'. The thrust means is constituted by a chamber 62 of sheath 1 6, which chamber is constantly subjected via port 24 to oil pressure during movement of jaws 5 and 6 for a clamping operation.

The vise is released by reversing the flow of oil in the general distributor 31, i.e. by feeding oil under pressure into conduit 34 thereby causing the pistons 9 and 12 of servo-motors 7 and 3, and hence jaws 5 and o, to move away from one another.

Of course, conduit 37 will have to be opened to the atmosphere by the solenoid-operated valve 33 to enable jaws 5 and 6 to be moved apart.

I claim:

1. A machine tool locating vise comprising,

a frame having a bore provided with iiuid pressure ports and an exhaust port,

iirst and second fluid cylinder and piston article clamping units,

a primary source of duid pressure operating in conjunction with valve means to move the piste-ns of said lirst and second article clamping units to article clamping position,

valve means in said bore comprising a sheath and a slidable valve telescoping therewith, said sheath and valve having portions exposed outside or the bore, and said valve havin-r an annular groove adapted to cooperate with said pressure ports to supply pressure to the second tiuid cylinder and piston article clamping unit and also communicating with said exhaust port,

and means actuated respectively by the exposed portions of the sheath and the valve to hold the pistons and clamping members in final adjusted relation.

2. A machine tool locating vise as claimed in claim l, wherein said means holding the pistons and clamping members in final adjustment includes, on the one hand, a connecting arm attaching said valve to said iirst clamping unit and, on the other hand, a rochable lever supported by said trame and having its opposite ends engaged by said sheath and said second clamping unit, said lever being supported at a point substantially closer to one end than the other to provide a demultiplication of the force exerted by said sheath.

3. A machine tool locating vise as claimed in claim 2, wherein said connecting arm provides a rigid attachment between said valve and said rst clamping unit, and means on said `valve for adjusting the positions of said valve and iirst clamping unit relative to one another to permit a modification of the position of the reference axis into which each workpiece is to be brought. Y

4. A machine tool workpiece locating vise, comprising,

a frame having a bore provided with a primary iuid PYSSSUIS passage,

an exhaust passage,

a clamping jaw including an article engaging stern and and actuating stern carried by a piston operating in a first cylinder having pressure and exhaust ports at opposite sides of the piston,

a centering jaw including a supporting stem 'and an actuating stern both connected to a piston of-larger diameter than said lirst mentioned piston and operating in a second cylinder having pressure and exhaust ports at opposite sides of the piston, said clamping and centering jaws operating in a plane parallel to said bore,

a sheath having limited slidable movement in said bore and having a iirst longitudinal groove communicating with said exhaust passage, said sheath being tubular at one end and exposed beyond the frame at the other end, said sheath also having a second longitudinal groove in communication with said primary tiuid pressure passavo, said iirst and second grooves provided with a secondary and primary port, respectively, extending inwardly through the wall of said sheath,

a valve member slidably mounted in the tubular portion of the sheath and having a medial annular groove adapted to span and communicate with said primary and secondary ports, one end of said valve member projecting from said frame,

a connecting arm attaching the projecting end of said valve member to the actuating stem of said clamping law,

an equalizing pressure port through said sheath and in constant communication with said annular groove on the one hand and connected on the other hand to said second cylinder,

a lever roclrabiy supported medially on the frame and having one end engaging the actuating stem of said centering jaw and the other end engaged by the exposed end of said sheath,

Fr f as and a source of Huid under pressure including a pair References Cited in the ie of this patent of valves, one of said valves supplying uid to said UNITED STATES PATENTS pressure port of said rst cylinder and also c0rnpressure port of said rst cylinder, said slidable valve member is moved to permi the flow of iuid from FOREIGN PATENTS s'd ir otthrofflsidgnni D' nl al pr mary p r uol a r1 u at move a C 430,825 Great Britain June 24, 1935 equalizing pressure port to the pressure port of said second cylinder. lo 875,395 Great Bumm Aug. i6, 1961 

1. A MACHINE TOOL LOCATING VISE COMPRISING, A FRAME HAVING A BORE PROVIDED WITH FLUID PRESSURE PORTS AND AN EXHAUST PORT, FIRST AND SECOND FLUID CYLINDER AND PISTON ARTICLE CLAMPING UNITS, A PRIMARY SOURCE OF FLUID PRESSURE OPERATING IN CONJUNCTION WITH VALVE MEANS TO MOVE THE PISTONS OF SAID FIRST AND SECOND ARTICLE CLAMPING UNITS TO ARTICLE CLAMPING POSITION, VALVE MEANS IN SAID BORE COMPRISING A SHEATH AND A SLIDABLE VALVE TELESCOPING THEREWITH, SAID SHEATH AND VALVE HAVING PORTIONS EXPOSED OUTSIDE OF THE BORE, AND SAID VALVE HAVING AN ANNULAR GROOVE ADAPTED TO COOPERATE WITH SAID PRESSURE PORTS TO SUPPLY PRESSURE TO THE SECOND FLUID CYLINDER AND PISTON ARTICLE CLAMPING UNIT AND ALSO COMMUNICATING WITH SAID EXHAUST PORT, AND MEANS ACTUATED RESPECTIVELY BY THE EXPOSED PORTIONS OF THE SHEATH AND THE VALVE TO HOLD THE PISTONS AND CLAMPING MEMBERS IN FINAL ADJUSTED RELATION. 